Such assemblies are used for converting rotational movements into translational movements. When such an assembly is designed for small loads, for instance in a motor vehicle for actuating ventilation nozzles or air outflow grids, the two components spindle and moving nut are preferably made of plastics. With regard to a small mounting effort it would be desirable to form the two components as injection-molded parts, one of which is inseparably connected with the other.
In principle, it is possible to directly apply one part onto another by injection-molding such that the two injection-molded parts are movable relative to each other. There can be used for instance a method of injection molding articles which consist of at least two parts, as it is known from DE 33 40 122 C2. In this method, a first injection-molded part is fabricated in a first mold, the same is then removed from the first mold and placed into a second mold. The first injection-molded part will cool in the process and solidify to such an extent that subsequently in the second mold the second injection-molded part can be injected into the first injection-molded part. The two injection-molded parts can thus movably, but inseparably be connected with each other.
Since the first injection-molded part already has solidified in part, before the second injection-molded part is formed, the first injection-molded part already has experienced part of its inevitable shrinkage, before the material for the second injection-molded part is injected. This can lead to the second injection-molded part getting jammed on the first injection-molded part, when the second injection-molded part now shrinks for its part. When the second injection-molded part is the moving nut, it will get shrunk onto the spindle upon solidification, so that the two components are very tight or are even blocked relative to each other.
Therefore, it is the object of the invention to provide an assembly comprising a spindle and a moving nut as described above, in which the movability between spindle and moving nut is not impaired, even if one of the components is applied on the other one by injection-molding or is injected into the other one.